DE102019210546A1 - Household appliance filter and household appliance with it - Google Patents

Abstract

A household appliance filter (3) has at least one full-bodied filter layer (7) made of a filter material (8) with reduced blocking and a material-related surface energy of 35 mN / m or less over at least part of its surface (6). A household appliance (2) has at least one household appliance filter (3). The invention is particularly advantageously applicable to laundry care appliances, especially laundry drying appliances.

Description

The invention relates to a household appliance filter which has a filter layer with a filter material with a surface energy of 35 mN / m or less. The invention also relates to a household appliance with at least one such household appliance filter. The invention is particularly advantageously applicable to laundry care appliances, especially laundry drying appliances.

Laundry dryers are known which have a process air duct equipped with a process air filter. During a drying process, lint and other particles (hereinafter referred to as particles) that detach from the laundry to be dried are carried along with the process air flow. The process air filter is used, among other things, to filter out particles from the process air flow that would otherwise disadvantageously spread into functional areas of the tumble dryer and be deposited there, e.g. on cooling fins of heat exchangers. Such filters currently have PET (polyethylene terephthalate) fabric as the filter material or filter medium.

In order to prevent the process air filter from being clogged by the particles deposited on it and then blocking the process air duct, it is also known to automatically clean the filter by applying water to it by means of a flushing device. In particular, the water can be condensate formed during drying. This cleaning on the device side means that the user no longer needs to manually clean the filter after each drying process.

During this cleaning, however, under certain environmental conditions, the disadvantageous situation can be that the filter openings are temporarily clogged with water between the condensate and the process air filter. This creates such a high flow resistance for the process air that the process air volume flow that is sufficient for a drying function can no longer be established. The filter is "blocked". This results in considerable disadvantages for the operating efficiency and performance of the clothes dryer.

DE 10 2008 055 086 A1 discloses a laundry drying device, comprising a sieve for sifting out bodies, in particular lint, from a process air duct of the laundry drying device and comprising a cleaning device for cleaning the sieve, the sieve being arranged at an angle in the room. The method is used to clean a sieve of a laundry drying device by means of a cleaning device for cleaning the sieve, the sieve being arranged obliquely in the room at an angle and a cleaning liquid being passed over the inclined sieve. The lint filter material is preferably made of metal or comprises metal. For use in a damp environment, such as in a tumble dryer or a washing machine, the fluff filter material can consist of corrosion-resistant material, in particular of a material that is corrosion-resistant to the action of lye or water. Stainless steel or aluminum can be used as the fluff filter material, which are temperature-resistant and, if necessary, can easily be coated with suitable finishing materials in a hydrophobic manner. Such a hydrophobic finish can be designed as a nano lacquer and / or a lotus effect on or on the lint filter material. The fluff filter material with the equipment can be present as a fabric, scrim or as a perforated foil or sheet.

EP 2 202 348 A2 discloses a household appliance sieve made of a basic sieve material with a hydrophobic coating for sieving out bodies, in particular lint, from a process water duct or a process air duct, the basic sieve material being made of a material that is resistant to temperatures of 160 ° C or more, the hydrophobic coating on or causes a surface energy of less than 35 mN / m on the sieve base material, in particular causes a surface energy of less than 28 mN / m.

DE 10 2008 010 517 A1 discloses a domestic appliance for drying laundry, in particular a tumble dryer or a washer dryer, which domestic appliance has a component around which process air can flow, the component having a substrate made of metal or plastic, which has a surface facing the process air. This surface has a coating that prevents the adhesion of a foreign particle.

DE 10 2008 041 998 A1 discloses a dryer, comprising a drying chamber for receiving moist material and a substantially closed process air duct for circulating process air through the drying chamber, which process air duct is a heat source for heating the process air before it enters the drying chamber and a heat sink for cooling the process air after it exits from the drying chamber as well as a first lint filter arranged between the drying chamber and the heat sink for catching lint from the process air, to which a first cleaning device is assigned. This first cleaning device has a collector for a liquid, a first flushing line connected to the collector, a first control element located in this first flushing line and a first distributor connected to the first flushing line for distributing conveyed through the first flushing line Liquid on the first lint filter and for collecting collected lint from the first lint filter, a first drainage line for draining the liquid with the collected lint from the first lint filter to the collector. A filter fabric of the lint filter has at least one property from the group comprising the properties of being hydrophobic, dirt-repellent and antibacterial. All the properties mentioned can be imparted to the filter fabric by an appropriate coating, it being possible for the coating to be formed by impregnation or plasma coating.

It is the object of the present invention to at least partially overcome the disadvantages of the prior art. In particular, the task is to provide a household appliance filter that can be produced inexpensively and is particularly easy to clean, which also shows a low probability of its filter openings becoming clogged with water in the long term.

This object is achieved according to the features of the independent claims. Advantageous embodiments are the subject matter of the dependent claims, the description and the drawings.

The object is achieved by a household appliance filter which has at least one full-bodied filter layer made of a filter material with reduced blocking and a material-related surface energy of 35 mN / m or less over at least part of its surface. The filter material with the surface energy of 35 mN / m or less is also referred to below as “blocking-reduced filter material” without loss of generality.

This makes use of the fact that the occurrence of the effect of the temporary clogging of the filter material with the condensate is significantly influenced by the surface energy properties of the filter material used and the associated wettability with water: the undesirable wetting of the filter material occurs less, the more different the surface tensions between the condensate (water) and the filter material.

It has been shown that with a surface energy of the blocking-reduced filter material of 35 mN / m or less or not more than 35 mN / m, a filter installed in a laundry dryer is significantly less blocked by condensate / water during a cleaning process than when it is used of PET as a filter material, which has a surface energy of approx. 43 mN / m. In this way, the effect of temporarily clogging the filter openings with water can be avoided and thus maintaining the operating and performance of the household appliance under conditions which lead to a considerable impairment of the performance of the household appliance with a conventional design of the filter with PET fabric would.

A full-bodied filter layer is understood to mean, in particular, a layer that consists entirely of the filter material with reduced blocking. The filter material with reduced blocking is therefore not in the form of a coating on a base material, but rather as a layered solid body, possibly with additives or admixtures. The filter openings are located in the filter layer. The use of a full-bodied filter layer has the advantage over a coating that it is easier and cheaper to manufacture. The full-bodied filter layer cannot, like a coating, lead to flaking from the base material. In addition, a solid material can be subsequently processed more precisely and in a more versatile manner than a base material can be coated.

A layer is understood in particular to be a geometry whose height or thickness is noticeably smaller than its plane extent, in particular at least ten times smaller. The layer can in particular be a layer with a thickness of not more than 1 mm, in particular not more than 0.5 mm, in particular not more than 0.25 mm, in particular not more than 0.1 mm. The layer can be a foil.

The household appliance filter can furthermore have a layer stack of at least two layers, of which at least one layer is a full-bodied filter layer. The at least one other layer can serve other functions, e.g. as a carrier, etc. The household appliance filter can in particular have several full-bodied filter layers stacked directly or indirectly on top of one another.

A "material-related surface energy" is understood to mean the surface energy of the filter material with reduced blocking and thus represents a material property. This does not mean a surface energy that results from a targeted microstructuring of the surface of the filter layer, e.g. to create a lotus effect. This achieves the advantage that wear, which frequently occurs in microstructures, with an associated strong reduction in surface energy does not occur, since the material as such has and also maintains the desired low surface energy. However, microstructuring can in principle also be provided in order to further reduce the surface energy.

The surface energy of the filter material with reduced blocking is in particular its surface free energy (SFE). A value of approx. 73 mN / m is assumed as the surface energy of water.

The household appliance filter is, in particular, a household appliance filter intended to be arranged in a process air duct of a laundry drying appliance. However, the filter is not limited to this and can, for example, also be provided to be arranged in a process air duct of another household appliance and / or in a process fluid duct.

It is an embodiment that the material-related surface energy of the filter material with reduced blocking is or causes 30 mN / m or less, in particular 25 mN / m or less, in particular 20 mN / m or less.

In one embodiment, the filter material with reduced blocking is polymer material, that is to say has one or more types of polymer. This can be produced in layers particularly easily and inexpensively.

It is an embodiment that the blocking-reduced filter material has or is PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride), PC (polycarbonate), PE (polyethylene) and / or PP (polypropylene). This is particularly advantageous because these substances typically have a significantly lower surface energy than PET, are easy to process and are widely available. The difference between the surface energies and water is consequently significantly greater than with "water / PET". A wetting of the surface with water is significantly worse with the materials listed above than with PET, which has a positive effect on clogging. This particularly applies to PTFE (SFE from approx. 18 mN / m - 20 mN / m) and PVDF (SFE from approx. 25 mN / m - 32 mN / m). In addition, these last two materials are particularly thermally and chemically resistant and durable. Especially when using PTFE as the filter material, blocking of the filter openings by water could be completely avoided.

In one embodiment, a filter surface of the filter has at least one filter layer made of the filter material with reduced blocking over the entire surface. This enables particularly simple production and particularly effectively prevents the filter openings from being blocked by water. A filter surface can be understood to mean in particular the surface with a filter function that is present when the household appliance filter is viewed from above. Such a filter is also referred to below as a “full filter”.

It is an embodiment that a filter surface of the filter only partially or partially has at least one filter layer made of the filter material with reduced blocking. The remaining part of the surface can consist of (other) filter material with a surface energy of more than 35 mN / m, e.g. PET fabric. This makes use of the fact that only a relatively small (partial) filter area that is not clogged is often required in order to maintain an operating sequence of the household appliance - albeit possibly with significantly reduced effectiveness. Such a filter is also referred to below as a “mixed filter”. The mixed filter can have the advantage that it is cheaper than a full filter. Alternatively or additionally, it can advantageously be the case that the other filter material has a higher air throughput in normal operation (outside of wetting with water) than the filter material with reduced blocking, so that the mixed filter then also has a higher air throughput than the full filter. The other filter material can, for example, have a surface energy of 40 mN / m or more.

It is a further development that the area proportion of the filter material with reduced blocking or the at least one associated filter layer is not more than 90%, in particular not more than 80%, in particular not more than 70%, in particular not more than 60%, in particular not more than 50 %, in particular not more than 40%, in particular not more than 30%, in particular not more than 20%, in particular not more than 10% of the total filter area of the filter.

It is an embodiment that the full-bodied filter layer is an extruded layer. This configuration has the advantage that the filter layer does not have an overlay or intersection of individual threads, compared to fabrics, but a comparatively smooth surface to which particles adhere less, which in turn is advantageous both for device-side cleaning and for cleaning by an end user is. This also advantageously results in a lower increase in the pressure loss of the filter between maintenance intervals. In addition, production by means of extrusion can be implemented particularly inexpensively.

It is an embodiment that filter openings have been subsequently introduced into a closed surface of the solid material layer or the filter openings are subsequently introduced filter openings. The subsequent introduction can have been achieved, for example, by cutting, punching, laser cutting and creates the filter layer from the material layer. The subsequent introduction enables a particularly precise or precise shaping of the filter openings. For example, a filter opening through slots and then bending the opposite edges of the slot open in opposite directions.

In a further development, the filter openings can have a maximum extension of 1 mm, in particular 0.75 mm.

The material layer can be a layer produced in the manner of a band, in particular a material layer separated from an endless band or quasi-endless band.

The object is also achieved by a household appliance that has at least one household appliance filter as described above. The household appliance can be designed analogously to the filter and has the same advantages.

In one embodiment, the household appliance is a laundry drying appliance and the household appliance filter is arranged as a particle filter or lint filter in a process air duct. The household appliance filter achieves a better energetic behavior of the laundry drying appliance, and expanded possibilities for a procedural design of a drying process are made possible. The laundry drying device has in particular a rinsing device for automatically cleaning the household appliance filter with water, in particular condensate.

The clothes drying device can be a pure clothes dryer or a washing / drying combination device (“washer-dryer”).

However, the invention is not limited to this: the filter can also be provided as a filter for retaining particles from condensate or other liquid, for example before the condensate flows into a collecting pan. In addition, the filter can be used in other types of household appliances such as dishwashers, washing machines, etc.

It is an embodiment that the laundry drying device has a heat pump. In particular, it can then be advantageous if only a partial area of the filter surface has the blocking-reduced filter material or at least one solid material layer and otherwise consists e.g. of PET fabric. This makes use of the fact that it has been proven that only a relatively small (partial) filter area that is not clogged is required to enable a process air volume flow that avoids so-called freezing of the heat exchanger. The partial area covered with the blocking-reduced filter material can in particular make up less than half of the total filter area, in particular less than 40%, in particular less than 30%, in particular less than 25%, in particular less than 20%, in particular less than 10% of the total Filter area.

• 1 zeigt als Schnittdarstellung in Draufsicht einen Prozessluftkanal eines Wäschetrocknungsgeräts mit eingesetztem Haushaltsgerätefilter; und
• 2 zeigt in Schrägansicht eine mikroskopische Aufnahme einer Filterlage.

The properties, features and advantages of this invention described above and the manner in which they are achieved will become clearer and more clearly understood in connection with the following schematic description of an exemplary embodiment which is explained in more detail in connection with the drawings.

• 1 shows, as a sectional illustration in plan view, a process air duct of a laundry drying device with an inserted household appliance filter; and
• 2 shows a microscopic image of a filter layer in an oblique view.

1 shows a process air duct as a sectional view in plan view 1 a clothes drying machine 2 with inserted household appliance filter in the form of a particle filter or fluff filter 3 . The laundry dryer 2 can be a tumble dryer equipped with a heat pump (not shown) or a washer-dryer. The fluff filter 3 can be inclined in the process air duct 1 be arranged, but is installed horizontally in the present case. The fluff filter 3 has an outer annular frame 4th on, by means of which it is in the process air duct 1 is used.

The fluff filter 3 has a filter surface in plan view 5 , 6th with two sub-areas, namely an annular outer sub-area attached to the frame 5 and a central one, from the outer face 5 surrounding circular inner partial area. The inner face 6th is smaller than the outer face 5 and is, for example, only 30% or less of the total filter area 5 , 6th .

The outer face 5 consists of PET fabric, while the inner partial surface 6 has at least one filter layer 7th which has been produced entirely by extrusion from PTFE as the filter material. PTFE has a material-related surface energy (SFE) between 18 mN / m and 20 mN / m.

2 shows a microscopic image of the filter layer in an oblique view 7th . The filter layer 7th is a thin layer of PTFE 8th formed into the subsequent filter openings 9 have been introduced. The filter layer 7th has a comparatively smooth surface in which, in particular in comparison to fabric, there is no crossing of individual threads.

Of course, the present invention is not limited to the embodiment shown.

In general, “a”, “one” etc. can be understood as a singular or plural number, in particular in the sense of “at least one” or “one or more” etc., as long as this is not explicitly excluded, for example by the expression “exactly a "etc.

A number can also include exactly the specified number and a customary tolerance range, as long as this is not explicitly excluded.

List of reference symbols

1

Process air duct

2

Laundry drying device

3

Lint filter

4th

frame

5

Outer partial area of a filter area

6th

Inner partial surface of a filter surface

7th

Filter layer

8th

PTFE layer

9

Filter opening

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102008055086 A1 [0005]
• EP 2202348 A2 [0006]
• DE 102008010517 A1 [0007]
• DE 102008041998 A1 [0008]

Claims (10)

Household appliance filter (3) which has at least one full-bodied filter layer (7) made of a filter material (8) with reduced blocking and a material-related surface energy of 35 mN / m or less over at least part of its surface (6). Household appliance filter (3) after Claim 1 , the material-related surface energy of the filter material (8) with reduced blocking being 30 mN / m or less, in particular 25 mN / m or less, in particular 20 mN / m or less. Household appliance filter (3) according to one of the preceding claims, wherein the filter material (8) with reduced blocking comprises PTFE and / or PVDF. Household appliance filter (3) according to one of the preceding claims, wherein a filter surface of the household appliance filter (3) has at least one filter layer (7) made of the filter material (8) with reduced blocking over the entire surface. Household appliance filter (3) according to one of the Claims 1 to 3 , wherein a filter surface (5, 6) of the household appliance filter only partially (6) has at least one filter layer (7) made of the filter material (8) with reduced blocking. Household appliance filter (3) according to one of the preceding claims, wherein the solid filter layer (7) is an extruded layer. Household appliance filter (3) after Claim 6 , wherein the filter openings (9) of the filter layer (7) are subsequently introduced filter openings. Domestic appliance (2), having at least one domestic appliance filter (3) according to one of the preceding claims. Household appliance (2) Claim 8 , wherein the household appliance (2) is a laundry drying appliance and the household appliance filter (3) is arranged in a process air duct (1) of the laundry drying appliance. Household appliance (2) Claim 9 , wherein the laundry drying device comprises a heat pump.

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